LAVALLE, Juan (lah-val'-yeh), Argentine soldier; born in Buenos Ayres, 16 October, 1797; died in Jujuy, 9 October, 1841. He entered the army at the age of sixteen, fought in 1814 and 1815 against, Jose Artigas, and in 1817-'18 in the battles of Chacabuco and Maipu. In 1820 he embarked for Peru with the forces that were sent by Buenos Ayres to aid the revolutionists. He was promoted major for gallantry in action, took command of his regiment at Moquegua, where its colonel was wounded, and effectively protected the retreat of the army. He returned to Buenos Ayres in 1823, and shared in the campaign against Brazil from 1825 up to the conclusion of peace in 1828. His conduct at the battle of Ituzaingo gained him the grade of coronel mayor. About this time he began to take part in politics, headed a revolt against Colonel Dorrego, governor of Buenos Ayres and chief of the Federalists, and overturned his government, 1 December, 1828. The governor was again defeated at Navarre, and Lavaile, obtaining possession of his person by treachery, had him immediately shot. On 26 April, 1829, Lavalle was defeated by Estanislo Lopez y Santa-Fe, and forced to withdraw from Buenos Ayres. In 1838 a French expedition was sent out against the dictator Juan Manuel de Rosas, and the city of Buenos Ayres was declared blockaded. Lawdle was chosen commander-in-chief of the forces of Uruguay, united to those of Corrientes, and marched on Buenos Ayres; but when within sight of the city he suddenly gave orders to retreat to Sante-Fe. Rosas, who had been much alarmed by the approach of the enemy, sent his lieutenant, Oribe, to attack that city, and meanwhile Lavalle learned that a treaty of peace had been signed between the French and the governor of Buenos Ayres, 29 October, 1840. He rejected the offer of an asylum and a pension that was made him by the French representative, and determined to continue the war against Rosas unaided. But he was pursued by a superior force, defeated at Quebracho-Herrado on 28 November, and again on the plains of Famailla, 19 September, 1841. With great difficulty he reached the capital of the province of Jujuy, escorted by about 100 soldiers, when he met a party of the enemy and was killed in a house where he had taken refuge.